首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1448558篇
  免费   100088篇
  国内免费   3004篇
耳鼻咽喉   21465篇
儿科学   44022篇
妇产科学   41219篇
基础医学   204428篇
口腔科学   43602篇
临床医学   122402篇
内科学   283020篇
皮肤病学   33563篇
神经病学   117700篇
特种医学   58276篇
外国民族医学   435篇
外科学   224560篇
综合类   31521篇
现状与发展   6篇
一般理论   474篇
预防医学   98628篇
眼科学   33834篇
药学   107821篇
  4篇
中国医学   3169篇
肿瘤学   81501篇
  2018年   14439篇
  2017年   11813篇
  2016年   13432篇
  2015年   14362篇
  2014年   19369篇
  2013年   30023篇
  2012年   39395篇
  2011年   41978篇
  2010年   24607篇
  2009年   22790篇
  2008年   40584篇
  2007年   44069篇
  2006年   44272篇
  2005年   42974篇
  2004年   41620篇
  2003年   40538篇
  2002年   39895篇
  2001年   66987篇
  2000年   69521篇
  1999年   57795篇
  1998年   15595篇
  1997年   14255篇
  1996年   13556篇
  1995年   12745篇
  1994年   11983篇
  1992年   43276篇
  1991年   41725篇
  1990年   40973篇
  1989年   39974篇
  1988年   37342篇
  1987年   36783篇
  1986年   35235篇
  1985年   33593篇
  1984年   25286篇
  1983年   21431篇
  1982年   13069篇
  1981年   11910篇
  1979年   24242篇
  1978年   17374篇
  1977年   15134篇
  1976年   13658篇
  1975年   15529篇
  1974年   18354篇
  1973年   17789篇
  1972年   16983篇
  1971年   15905篇
  1970年   15095篇
  1969年   14503篇
  1968年   13622篇
  1967年   12189篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
32.
33.
34.
35.
To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal τ. MK-801 (a noncompetitive NMDA receptor antagonist) did not atenuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of τ. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of τ-1 immuno-reactivity was observed in CA3 and CA1 s. oriens, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in τ hyperphosphorylation.  相似文献   
36.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease.  相似文献   
37.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
38.
39.
40.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号